1. Field of Invention
This invention relates to reclamation processes. More particularly, this invention relates to processes for treating scrap film so that the film can be reused in plastic molding and extrusion applications.
2. Prior Art
For many years SARAN- or vinylidene chloride polymer-coated materials have been known to be useful in the food packaging industry. Because of the extremely large volume of film produced for these packaging applications, of necessity a large volume of scrap film results. Scrap film is produced, for example, as a result of wastage or trimming which occurs during film processing.
While SARAN-coated films have excellent properties for use in food packaging, the post-treatment or reclamation of these films has to date not allowed the use of the reclaimed materials in conventional plastic extrusion and molding equipment. This is due in large part to the fact that the presence of chlorine in the SARAN coating on the laminated film causes pitting, or other degradation of the molds or extruder surfaces which come into contact with the reclaimed polymer. Thus, while the remolding and reuse of conventional scrap film is well known, no commercially viable process has been available for the molding of scrap, SARAN-coated, polyolefinic films.
It is known that scrap polyolefinic film treated with a polychlorinated overcoating may subsequently be treated with lime to improve its usefulness in remolding applications. However, the lime treatment process is deficient in that it does not completely neutralize the chlorine present in the scrap film. As a result, when attempts are made to mold or extrude this scrap film, the processing equipment continues to be subject to pitting and other degradation on the equipment surfaces which are exposed to the SARAN-coated, scrap film.
Accordingly, it is an object of this invention to provide a process which will allow the remolding of SARAN-coated, scrap, thermoplastic films.
It is another object of this invention to develop a process to allow the use of otherwise discarded scrap polymeric film.
It is yet another object of this invention to prepare molded plastic products in conventional molding equipment employing scrap, processed film, which scrap film will not degrade molding equipment.
These and other objectives are obtained by employing the process of the instant invention.